Circuit breaker



y 1941- E. R. CAPPELLE 2,242,232

CIRCUIT BREAKER Filed Nov. 1, 1937 2 Sheets-Sheet 1 y 1941-v E. R. CAPPELLE 2,242,232

CIRCUIT BREAKER Filed Nov. 1, 1937 2 Sheets-Sheet 2 zm/ma e/e M g |I Patented May 20, 1941 UNITED STATES PATENT OFFICE CIRCUIT BREAKER Emil R. Cappelle, Chicago, 111.

Application November 1, 1937, Serial No. 172,080

19 Claims.

This invention relates to improvements in circuit breakers.

Oneobiect oi the invention is to provide an improved thermostatically responsive circuit breaker of simple and economical construction.

Another object of the invention is to provide a circuit breaker of simple, compact, economical construction which may be operated repeatedly by overloaded circuits or by current flow above a predetermined amperage and repeatedly reset without renewal of its parts. 7

A further object of the invention is to provide a circuit breaker provided with a manually resetting device comprising a member which moves from normal position to indicate an open circuit but which member, if its movement to indicating position is obstructed'by any means or is manuallv held in normal position. will not prevent the circuit opening mechanism of the device from opening the circuit u on recurrence or continuance of circuit overload.

An additional object of the invention is to provide a circuit breaker having switch or contact mechanism housed within a casing which preferably is tamper-proof and through an opening in which casing operates a manually operable member i'or resetting the switch to closed position but which switch may open automaticircuit breaker having a pair of cooperating concentric contact elements which provide a relatively large contact area and which can be separated to break a circuit by means of an intermediate insulating member which snuiis the are which tends to form between the members upon the breaking of the circuit.

An additional object of the invention is to provide a circuit breaker mechanism which has no wires or like flexible connections which require soldering or welding to other parts and which mechanism is adapted for incorporation in switches, outlet receptacles or other relatively lowcost electrical devices.

In the drawings. certain embodiments of the invention' are disclosed for the purpose oi illus- "tia'tion, wherein:

Fig. 1 is a broken top plan view of a circuit breaker embodying the present improvements and of a type adapted to be screwed into a threaded socket;

Fig. 2 is a sectional view taken on line 2-2.55

of Fig. 1;

Fig. 3 is a sectional view taken on line 3-3 of Fig. 1;

Fig. 4 is a horizontal section taken on line 4-4 01' Fig. 3;

Fig. 5 is a section taken on line 55 of Fig. 16;

Fig. 6 is a broken sectional view taken on line 5-4 01' Fig. 1;

Fig. 7 is an enlarged broken sectional view of a lower portion 0! the contact members in the relation shown in Fig. 2;

Fig. 8 is a broken top plan view corresponding to Fig. 1 but with a heat responsive member shown in a position which eiiects the breaking of the circuit;

Fig. 9 is a broken view of the cap or cover 01' the device shown in Figs. 1 and 2 in detached relation and showing also the parts which are mounted on or carried by said cap;

Fig. 10 is a perspective view of the lower side of the cap;

Fig. 11 is a distended or exploded view of the parts of the circuit breaker;

Fig. 12 is a broken vertical sectional view. partially diagrammatic, showing the relation oi the operating parts oi the circuit breaker while the same are in circuit closing relation;

Fig. 13 shows the parts at the instant they reach circuit breaking relation;

Fig. 14 is a similar view illustrating a position of the parts succeedingthe position shown in Fig. 13 during movement of the operative Parts to circuit opening position;

Fig. 15 is a similar view showing the parts after having completed their movement from circuit closing to circuit opening position;

Fig. 16 is a similar view showing the device in circuit opening relation wherea button or resettingdevice is obstructed and retained in the position which normally indicates a closed circuit;

Fig. 1'7 is a bottom 'plan view of a terminal plug in which the present invention is embodied for protecting the lighting or heating or power device receiving current through the plug;

Fig. 18 is a sectional view taken on line iB-l8 of Fig. 17; I

Fig. 19 is a vertical sectional view or a structure embodying the present improvements and means which cooperate with the improved circuit breaker for converting the same into a. manually operable switch;

Fig. 20 is a view similar to Fig. 19 but illustrating the device in circuit opening position;

Fig. 21 is an elevation of aconductor connector embodying the present improvements and into which a conventional receptacle plug may be inserted for supplying current to an electrical device;

Fig. 22 is a sectional view of the device shown in Fig; 21 and illustrating the circuit thereof diagrammatically;

Fig. 23 is a plan view of a wall plug receptacle having a circuit breaker embodying the present invention incorporated therein;

Fig. 24 is a sectional view through the device shown in Fig. 23 and illustrating the circuit thereof diagrammatically; and

Fig. 25 is a perspective view of a modified thermostatic element adapted for use in structures embodying the present improvements.

The circuit breaker shown in Figs, 1 to 16, inclusive, is of a type adapted to be screwed into a conventional fuse outlet for protecting a circuit against predetermined overloads. The device comprises an outer casing ID of suitable material such as porcelain, Bakelite, or the like, on the exterior of which, as shown in Fig. 2, is a screw terminal II, a lower end Ila of which engages beneath a shoulder I01; of the casing. The manner in which the screw terminal H is retained in position on the casing ill will be described later. The interior of the casing I is provided with an integral upstanding tubular boss or post I2 through which extends the other terminal l3 having a contact head |3a at its lower end. The upper end of the member I3 is also provided with a head [3b which seats within a cup-like conducting brush member l4, the vertical walls of which are slotted as shown in Fig. 11 to provide resilient fingers Ma. The head I3b holds the conducting member [4 in position on the upper end of the post l2. Surrounding the post is an annular space IS. The upper end of the casing I0 is of somewhat enlarged diameter and comprises a cylindrical wall lilb. This construction provides a shoulder illc which is provided with a semi-circular rib [0d spaced outwardly from the inner edge of the shoulder as shown in Fig. 11.

The inner surface of the wall lllb may be provided, as shown, with an annular notch lOe into which may be snapped or pressed an edge of a closure or cap member indicated generally by the numeral l6. The cap is provided with a central passage Ilia and at its lower surface is shaped for attachment thereto of a thermostatic member and in one embodiment of the invention, a heating element. The thermostatic member is shown in perspective in Fig. 11 and is indicated generally by the numeral l1. The member is generally of open ring-like form and adjacent one end is provided with a loop formation llawhich is arranged to seat within an opening l6b formed in an integral lower extension No. The width of the member l1 and its shape are such that it extends around and may contact with an integral rib lBd which terminates at lie adjacent the extension l6c. In assembling the member I! in position, the loop formation Ila is merely pressed downwardly into the passage IN), the lit being substantially tight and the portions adjacent the loop contacting adjacent surfaces of the member I So to anchor the looped end against movement.

Extending downwardly from the rib formation I611 is an integral wall lGf which is offset inwardly from the outer periphery of the rib lGd but is concentric therewith. The wall adjacent the member lie is provided with an opening I89 to the casing after assemblage.

for receiving a rivet or like fastening means it,

by means of which a heating element I9 is attached in position on the cap. The heating element i9 is shown in perspective in Fig. 11 and, as will be seen, lies adjacent the outer surface of the wall lGf, the rivet l8 passing through the opening 19a.

When the parts are in assembled relation, it willbe seen that the thermostatic element ll abuts the outer vertical edge of the rib lGd at its upper edge and at its lower edge abuts therib "id of the casing. The heating element I9 is therefore disposed inwardly of the thermostatic element which-preferably is of the bimetallic type whereby emitted heat will be concentrated upon the inner metal of the thermostat for causing rapid expansion thereof and,

a somewhat radial movement of the free end I'Ib which extends inwardly over the annular passage l5 of the casing as shown in Fig. 2. It will be noted that the inwardly directed end I'Ib is disposed between the block-like formation I and the end Hie of the rib lid.

The inner wall of the depending flange i6f of the cap member is provided with a vertical recess or slot in depending from the outer face of which is a connector strip 20 having threads 20a adjacent its lower end of the same pitch as the threads of the shell II, the rivet head being accommodated by the slot liih. The strip 20 in the assembled device is secured to the heating element i9 by the rivet I8 and passes through a vertical opening log of the member III which communicates with a slot [0f formed in the exterior wall of the body of the casing. When the member 20 has been passed through the opening I By into the slot Illf as shown in Fig. 3, a transverse rib 20!) thereof closes the opening lflg to prevent entrance of dust and foreign matter into the interior of the circuitbreaker. In attaching the shell I l, its threads mesh with the threads 20a whereby the shell is held in position thereon although solder 2| is employed for preventing rotation of the shell with respect An extension 20c of member 20 rests on the wall I00 of the casing 10 and prevents imposition of excessive strain on the rivet [8 as the shell is secured into position. The other end of the heating element I9 is provided with an opening l9b for receiving a rivet 22 or the like, by means of which the element is electrically connected to a contact indicated generally by the numeral 23 which. in the embodiment of the invention illustrated. constitutes one of two cooperating switch members by means of which a .circuit is opened or closed. The contact 23 is formed of conducting material having an upper cylindrical portion 23a and a lower tapered portion which is slotted longitudinally to provide flexible contact fingers 23b. The cylindrical portion of the contact is provided with an outwardly formed portion 230 through an opening 23d in which the rivet 22 extends and holds one end of the element I! in firm electrical contact with the contact 23. The upper portion 23a of the contact is also provided with a horizontal box-like formation 23c having upper and lower walls 23 and 239 between which the inwardly directed movable end of thermostat I1 projects. The end llb of the thermostat is slidable horizontally between the wall 23! and 239 which restricts tilting or twisting movement of the thermostat on a horizontal axis. When the contact 23 is in assembled relation, it seats against the inner wail of the depending flange or wall ii! of the cap and extends downwardly into the annular passage it of the casing. The wall 239 rests upon the horizontal wall lflc of the casing, as shown in Figs. 2 and 3, while an end wall 22h of the boxlike formation 22c abuts a vertical wall of the member lie of the cap, while an opposite wall 22 abuts the end lie of rib lid as shown in Figs. 1 and 8 which prevents rotation of the contact with reference to the cap l4.

Slidable axially with respect to the post l2 but spaced therefrom is a second contact member 24 which is of conducting material and of tubular form and adapted to reciprocate with reference to the contact 14 and to be guided thereby. The external diameter of the contact 24 is such as to provide suitable electrical contact with the lower ends of the flexible contact fingers 232;

when the circuit breaker is in circuit closing position as shown in Fig. 2. The internal diameter of the contact 24 is such that it makes suitable electric contact with the flexible fingers I40 of the cup member i4 as shown in Fig. 2. This contact between the members l4 and 24 is maintained whether the member 24 is in circuit opening or circuit closing position with reference to contact 28.

The upper end of contact 24 is shown'of reduced diameter and threaded for convenient attachment to the lower threaded end of a resetting member 25 shown in the form of an insulating button. The member 2! is centrally recessed as at 25a, within which recess is located a spring 25b which seats at its lower end within the cup member l4 and at its upper end normally exerts pressure against the member 25 to move it upwardly. The button 25 is slidable through the opening or e "a in the cap N. The exterior diameter of the button 25 is shown as being the same as that of the contact 24, the two members forming, when assembled as shown in Fig. 2, a unitary member around which is disposed a cylindrical insulating spreader member 26 which is movable in a direction to engage the flexible arms 23b to spread them or distend them radially to force them out of contact with the contact member 24 for opening the circuit through the circuit breaker.

The upper end of the member 211s provided with a flange 26:; between which and the cap I! is located a spring 2'Iwhich tends to force the member 28 downwardly to wedge or spread the flngers 23b putwardly or radially as above mentioned. I The lower end of the contact 24 is reduced in diameter (see Fig. '1 for receiving an annular member 28 of insulating material having a ledge or shoulder 28a adapted to seat under the ends of the arms 23bto retain the member 24 in circuit closing position. The member 23 is shown attached to the member 24 by means of a flange 24a.

It will be seen that when the spring 21 forces the member 28 downwardly, the arms23b will be forced radiallyoutwardly from the shoulder 28::

.whereupon thespring 25b will force the button Fig. 14 showsthe parts partially moved upwardly under the action of the spring 23b which is of greater strength than the spring 21 so that as the ledge 28a engages the lower end of the member 26, the latter is also carried upwardly against the action of the spring 21 and thereby compressing the latter. Fig. 15 shows the mechanism in final circuit breaking position.

For the purpose of retaining the member 20 normally in the position shown in Figs. 2 and 12, suitable means are provided which are actuatable to releasing position by the thermostat II. In the embodiment of the invention shown, such holding and releasing is in the form of a catch member He which is shown as integral with the thermostat and carried by the free inwardly directed end I'Ib thereof. This end ilb extends through the box-like formation 28c of the contact 22 and is slidable upon the lower wall 230 thereof which spaces the lower edge of the thermostat II from the wall III and renders it freeLv movable under the expanding action of the heat generated by the heating element It. This end of the thermostat is reduced in the vertical dimension. forming a shoulder "d which abuts the upper wall 28! for limiting inward movement of the end I lb. The walls 23f and 23a prevent tilting or twisting of the thermostat l1 upon a horizontal axis under the thrust of the spring 21.

When the device above described has been screwed into a socket, current through the breaker flows through terminal I3, conducting member i4. contact 24 to the cooperating contact 23. From this contact it flows through theheating element l9 and thence through the conductor strip 20 to the shell H.

The thermostat is so calibrated that it moves the catch i'ic out of engagement with the cooperating rib or flange 20a when subjected to the heat generated by current of predetermined amperage flowing through the heating element I. For example, when the circuit breaker is inthe form shown in Figs. 1 to 11 and is intended to be used as a substitute for a conventional screw screw type fuse, the calibration of the thermostat with reference to the heating element is such that the heat generated by a normal current load will be insufficient to cause the thermostat to move the catch l'lc out of supporting relation with the flange 26a and will hold the mechanism in the positions shown in Fig. 2. Upon a predetermined current overload, however, or a short circuit, the thermostat will move the catch llc out of supporting position with reference to the member 26a whereupon the spring 27 will force the member 26 downwardly which spreads the arms 23b and opens the circult. The spring 25b then forces the button 25 and the.contact 24 upwardly to the position shown in Fig. 15. The button thus indicates that the circuit in which a particular circuit breaker is installed has been opened. When the cause of the overload or the short circuit has been determined and corrected, the button pressed inwardly from the position shown in Fig.

15 to the positionshown in Figs. 2 or 12. During the inward movement of the button, the insulating member 28 spreads the fingers 23b apart until the ledge 28a is beneath the lower ends of the fingers whereupon the latter snap back into circuit closingcorztact with member 24, thus providing a quick inalxecf circuit. During such downward movement or the button 23, the catch member i'i'c will engage the flange 26a and retain the member 26 in the upper position. Should the button 25 be pressed inwardly before the cause of the circuit overload or the cause of a short circuit is remedied, the arms 2311 will snap into contact with the contact 24 as described and reestablish the circuit but due to the heavy surge of current through the device,

the thermostat will again release the catch or.

trip member He whereupon the spring 21 will force the member 25 downwardly to again open the circuit. This may happen before ones fingers are removed from the bottom 25.

Fig. 16 shows the member 26 moved to circuit opening position but with the button held in the position which normally indicates a closed circuit. As stated, it may be held in such a position by ones finger in attempting to close a circuit before remedying the cause of the short or circuit overload. In said figure, however, an object 29 is shown in position holding the button inwardly.

This object may be any thing which inadvertently restrains outward movement of the button under the action of the spring 2512. It will therefore be seen that the mechanism described protects a circuit from dangerous overloads and normally indicates that the circuit has been opened but that the circuit may be opened independently of the indicating means which, in the present embodiment, is the resetting button 25.

The foregoing description of the invention has dealt with an embodiment of the invention in a circuit breaker. of the screw base type but it will be obvious that the invention may be em bodied in other forms of devices for protecting electrical apparatus or equipment or wiring systems from excessive current loads. In Figs. 17 and 18, for example, the invention is shown as being embodied in a receptacle plug indicated generally by the numeral 33. The circuitbreaking mechanism of the plug 33 is the same as described above and will not be redescribed but its parts are indicated by corresponding reference characters. In Fig. 18, the prongs or plug-in terminals 3i and 32 of the plug are shown attached to the latter for. convenience in attaching a lamp, flat iron or other utensil to a conventional wall outlet receptacle. The terminal 3! is shown attached to the member l3 while the terminal 32 is attached to the base of the plug by a rivet 33.

, An electric cord 34 from the receptacle passes through a passage a of the plug, one wire of which is attached as by a screw 35 to the terminal 32 while the other wire is attached by a screw 36 to a conductor 31 which extends through an opening 38 into contact with the rivet i8. When the terminals 3| and 32 have been inserted in an outlet receptacle, current may flow through terminal 3|, conductor 13 to the cup l4, thence to the circuit breaker contact 24 and to the cooperating contact 23 which is connected to one end of the heating element 19 by rivet 22. The opposite end of the heating element is connected by rivet l8 to the conductor strip 31 and thence the current flows through one of the conductor wires to the utensil and back through the other wire to the terminal 32.

Figs. 19 and 20 diagrammatically disclose the circuit breaker in conjunction with mechanism which enables the circuit breaker to be used as a switch for opening the circuit while not interiering with its functioning in breaking a circuit automatically upon predetermined overload. In

these figures, the circuit breaker mechanism is displacing the thermostat member i1 from its usual position for releasing the spreader member 23 for operation by a spring 21. The manually operating mechanism mentioned may comprise a push button 4i which is held normally in position as shown in Fig. 19 by a spring 42. When it is desired to open the circuit, the button is pressed downwardly, the button operating a bell crank lever 43 which is pivoted at 44 to a portion of the casing 40. The upper arm 45 of the lever engages the inner surface of the thermostatic member I! adjacent itsiree endand swings the catch member He outwardly to release the member 26 whereupon the circuit is opened by the breaker mechanism in the same manner as it is opened when the thermostat moves under the action of heat generated by current above a predetermined amperage. To close the circuit with such an arrangement, the push button 25 is pressed downwardly until the member 28 is engaged by the lower ends of the flexible contact arms 23b of member 23 as above described. Fig. 20 illustrates the device in circuit opening position. The circuit of this embodiment of the inyention is shown diagrammatically in the figgures. One conductor 45 is connected to the terminal I30. while the, other conductor 45 is connected to the contact member 23 as by means of a heating element 41 shown diagrammatically, but which may correspond structurally with the element IQ of the preceding figures. Numerals 45a, 46a indicate diagrammatically conventional binding posts or terminals to which are connected conductors for supplying current to a currrent consuming device to be controlled by the combined' switch and circuit breaker.

Figs. 21 and 22 show the circuit breaker embodied in an electric outlet receptacle which is in the form of a plug and which may be plugged into a conventional wall outlet. This device is indicated generally by the numeral 48 and comprises a suitable insulating casing 49 in which the circuit breaker is locate i as shown in Fig. 22 but illustrated by dotted lines in Fig. 21. Terminals 50 and 5| are adapted to be plugged into a wall outlet receptacle while socket members 52 and 53 are adapted to receive terminals of a conventional receptacle plug which is connected with a conductor of any electric appliance. The circuit of the device shown is similar to that described above in connection with Figs. 19 and 20. -When the device 48 is plugged into a wall receptacle, current may flow from terminal 50, to conductor 54 and to terminal receptacle 53, thence through a plug inserted in the outlet receptacles 52 and 53 through the connected appliance and back through terminal 52 to the heating element 41 to contact 23. From contact 23 it flows to contact 24 through the circuit breaker, as'above described, to the terminal 5|.

The form of the invention shown in Figs. 23 and 24 is similar to that shown in Figs. 21 and 22 except that in Figs. 23 and24, the circuit breaker is shown embodied in a wall outlet of the type usually mounted in outlet "boxes by means of a transverse strip or strips 55. In this form of the invention, an insulating casing 56 carries the receptacle terminals 51 and 58, the former of which is connected to a heating element 41 and the other of which is connected to a terminal post 59.. The terminal I3 of the circuit breaker is connected to a second terminal post 50 by a conductor 5|. The current supply lines are, of course, connected to the posts 59 and 50 to supply current to the electric appliance whose plug is inserted in the members 51 and 58, the current flowing through the circuit breaker as above described so that in the event of a'short or an overload, the circuit will be broken.

Fig. 25 is a perspective of a modified form of thermostatic member which, when used, eliminates the necessity of the heating element Is. As shown, the thermostatic element indicated generally by numeral 62 is provided at its movable end with a catch member 62 which may correspond in construction and function with the catch member We of the above described embodiments of the invention. The element is slotted from its opposite or flxed end throughout substantially its entire length. This construction provides two legs 62:; and 62b which are connected in the circuit of the circuit breaker so that the current flows through both legs of the heating element. Upon overload, the heat generated causes a rapid movement of the free end of the element to move the catch 83 out of position wherein it supports the spreader member 25, the thermostatic metal being ofthe light resistance type.

The construction of the circuit breaker in its various forms as above described is such that it can be manufactured and assembled at relatively low cost.

It will be noted that in assembling the device only the terminal I! and brush or conductor cup l4 are initially installed in the casing in. All the other operating parts of the device are assembled in the cap IS. The heating element is is attached by rivet 22 to the contact 23 and rivet ll inserted in its opening with the head inward and the projection portion partially expanded to retain it in position or it may be molded in such position. Button 25 and contact 24 then are secured together and passed through spring 21 and spreader member 26. The button is then passed through the opening of the cap to fully compress the spring 21 and is held in that position. The contact 23 is placed in position in the cap. The projecting end of rivet I8 is passed through the opening in the other end of the heating element and the conductor strip 20 placed in position on the rivet which is then riveted over. The loop "a of the thermostat i1 is then pressed into the receiving recess lib and the free end passed through the box-like portion 22c to dispose the catch 230 in engaging position with the flange 26a. 'of the spreader. Upon release of the button 25, the parts are held in the assembled position shown in Fig. 9. The cap assembly is then inserted in the casing, a spring 25b having been placed in the conductor brush or cap member l4. During the insertion of thecap assembly, the conductor strip 20 passes through the slot lie which locates or guides the parts of the assembly into their proper positions with reference to the casing Ill. The cap is then depressed against the spring 25b until the edge of the cap snaps into the groove Ille. It thus is not necessary to make any soldered or screw connections in the relatively small space available within the casing, the screw shell ll being screwed into position and secured to the strip 20 by solder set repeatedly eliminates the expense and annoyance incident to the replacement of blown fuses. Since the device can be reset to circuit closing position merely by pressing in the indicator button 25, there is no necessity for removing the device from its socket after initial instal-' lation. The displacement of the button to the outward position shown in Fig. 15', upon opening a circuit by the device, facilitates the ready determination of the circuit in which a short has occurred or in which an overload was imposed. The arrangement whereby the member 26 can be actuated to open the circuit independently of the outward movement of the button is a desirable safety feature which prevents damage to wiring or electrical equipment should an attempt be made to close the circuit before correcting the cause of the circuit overload.

The response of the thermostat to the heat of s an overloaded circuit is rapid due in part to the fact that the heating element I8 is in the form of a flat ribbon substantially co-extensive with and of the same area as the movable portions of the thermostat and arranged substantially concentrically with respect thereto. The space between the heating element and thermostat is practically sealed by the relation of those members to the ribs llld and lid when the device is in normal or circuit closing relation and since the metallic strip of the thermostat having the greater c0- eflicient of expansion is disposed inwardly. the heat generated by an overload will cause quick response by the thermostat in releasing the device to circuit opening position, .the releasing action being supplemented by suitable inclinations of the contacting portions of the catch He and the flange 2611. As the thermostat moves out of contact with the ribs ltd of the cap and rib llld of the casing, the heat is dissipated by radiation from the thermostat to the cooler air in the annular chamber into which the thermostat moves and therefore quickly returns to the normal position in which it engages the flange 26a when the button 25 is again depressed to close the circuit.

It will be observed also that the construction is such as to quickly make and break the circuit. When the button isprassed downwardly to circuit closing position, the ends of the flngers 22b snap past the member 28 and thus effect a quick make of the circuit, the member 28 being a rounded lower edge which wedges the fingers outwardly during the downward stroke of the contact 24. When the circuit is broken by the auto. matic operation of the device upon the descent of the member 28, the circuit is broken rapidly and since member 26 is of insulating material, it tends to quench arcing which may take place between the contacts 25 and 24 since. as shown in Figs. 13 and 14, it is moved into a position interposed between'the contacting areas of said cont-acts. The movement of the member 26 into arc-quenching position is extremely rapid since it continues to move downwardly after releasing the arms 22b from the ledge 25a as the contact 24 starts upwardly under the action of the spring 25b. During the flnal portion of the upward movement of member 26 and button 25, the spring 2! acts as a bufler and cushions the thrust of spring 25b. The downward movement of the member 26 under action of the spring 21 is arrested upon engagement of the member with the ledge 22a, in which position of the member 25, the lower portion of contact 24 is efl'ectively insulated from the contact 23 in addition to being spaced therefrom.

While I have shown and described certain embodimerls and adaptations of the present improvements for the purpose of illustration, it will be apparent that various changes in construction and arrangement of parts may be resorted to without departing from the spirit of the invention.

I claim:

1. A circuit breaker comprising a pair of separable circuit closing contacts arranged concentrically one of said contacts being spring actuatable in an axial direction and the other comprising a plurality of flexible fingers adapted to engage the periphery of the first contact to close a circuit therethrough, an annular insulating member movable in a direction axially of said contacts from an inoperative position to a position between the contacts to move the ends of said fingers radially to release the spring actuatable contact and to open a circuit through the same, means for normally retaining said member in the inoperative position, and a thermostatic member responsive to current overloads for effecting the release of said member from said retaining means.

2. A circuit breaker comprising a pair of concentric contacts, one of said contacts being radially resilient and arranged for separating movement with respect to the other, said other contact being axially movable, a spring actuated insulating member movable between said contacts upon overload of the circuit for separating the same and releasing said axially movable contact, means for retaining said member in inoperative position, and a thermostatic member responsive to overload of the circuit for effecting the release of said member.

3. A circuit breaker comprising a casing, a pair of circuit closing contacts therein one of said contacts comprising radially movable fingers and the other being axially movable, thermostatically controlled spring actuated mechanism therein for effecting radial movement of said fingers and separation of said contacts upon circuit overload, and a spring actuated resetting member secured to said axially movable contact arranged to move outwardly of said casing upon the separation of said contacts and to shift said movable contact axially.

4. A circuit breaker comprising a casing, a pair of circuit closing contacts in said casing, a spring actuated member, one of said contacts being carried by said member, the second contact being arranged to. engage said first contact for closing a circuit and to retain said member in operative position against the action of the actuating spring thereof, a second spring actuated member arranged to move said second contact to release said first member, means for retaining said second member in inoperative position, and a thermostatic member arranged to release said retaining means upon circuit overload whereby said first movable member can move said first contact outof circuit closing position.

5. A circuit breaker comprising a pair of relatively movable circuit closing contacts, a spring actuated member for moving one of said contacts to break the circuit, a second spring actuated member for moving the-other contact out of normal circuit closing position and simultaneously restoring said first mentioned member to its normal position against the action of the spring thereof, and thermostatically controlled means for releasing said first mentioned member from said normal position upon an overload of the circuit.

6. A circuit breaker comprising a pair of circuit closing contacts. a thermostat responsive to circuit overloads, and means controlled by said thermostat for separating said contacts upon an overload of the circuit, said means comprising a pair of spring actuated members one of which is restrained against spring movement by said thermostat and the other is restrained by one of said contacts, the arrangement being such that upon overload of the circuit said thermostatcontrolled means is released by said thermostat and eifects separation of the contacts and release of the other spring actuated member and the latter restores said means to original posi-' tion and moves the other contact out of circuit closing position with respect to said first contact.

7. A circuit breaker comprising a pair of relatively movable circuit closing contacts, a thermostat responsive to circuit overloads, and means controlled by said thermostat for effecting the separation of said contacts upon an overload of the circuit, said means comprising a spring actuated member carrying one of said contacts and arranged to be retained against spring movement by the other of said contacts, a second spring actuated member adapted for retention against spring movement by said thermostat during normal current loads and for release upon a circuit overload and adapted to move saidsecond contact to release said first member for spring movement thereof to move said first contact out of circuit closing position, the spring of said first member being capable of returning said second member to original position against the action of the spring thereof.

8. A circuit breaker comprising a casing, a plunger thereon spring actuated outwardly of said casing, a contact carried by said plunger, a second movable contact arranged to retain said plunger in position against the action of the spring thereof and engage said first contact for closing a circuit, a spring actuated member arranged for moving said second contact away from said first contact for releasing said plunger, and a thermostatic member provided with means for retaining said spring actuated member in position against the action of the spring thereof during a-normal circuit load and to release said member upon an overload to effect the separation of the contacts to break the circuit and initiate the movement of said plunger outwardly oi. the casing.

9. A circuit breaker comprising a casing, a plunger therein spring actuated outwardly of said casing, a contact carried by said plunger, a movable contact in said casing arranged to engage said first contact to close a circuit and retain said plunger in position against the action of the spring thereof during a normal circuit load, a thermostatic member responsive to circuit overloads, and a spring actuated member arranged to be retained by said thermostat in spring retracted position during normal circuit loads and to be released upon circuit overload whereby the spring thereof moves said member in a direction to engage said second contact and moves the same away from said first contact to open the circuit and effect the release of said plunger for movement by the spring thereof outwardly of the casing, said *plunger'having means for engaging said member for returning the same to spring retracted position against the action of the spring thereof.

10, A circuit breaker comprising a casing, a pair of circuit closing contacts therein, a thermostatic member responsive to circuit overloads, and a pair of spring actuatable members in said casing, one arranged for retention in spring retracted position by 'one oisaid contacts and the other by means controlled by said thermostat, the arrangement being such that upon a circuit overload the latter spring actuatable member is released for movement by the spring thereof in a direction to effect release of the other member and separation of the contacts to open the circuit and said latter member effects the return of the first member to spring retracted position.

11. A circuit breaker comprising a pair of circuit terminals, a pair of circuit closing contacts each electrically connected with one of said terminais, spring actuated insulating means for separating the contacts to open a circuit through said terminals, a thermostatic member responsive to current overload, a catch for retainin said spring actuated means in position against the action of the spring thereof during normal circuit loads, said catch being movable by said thermostatic member to release said spring actuated means upon circuit overloads whereby said means can eflect theseparation of said contacts to open the circuit, and means for moving one 01' said contacts in an axial direction upon separation of said contacts, said movable contact during the movement thereof by said last mentioned means being arranged to engage said insulating means and restore the same to original position for re-engagement with said catch.

12. A circuit breaker comprising a pair of cooperating concentric circuit closing contacts having annular contacting areas and inter-engaging means, the outer of said contacts being radially distensible, an annular member having means for moving the same in an axial direction intermediate said contacts to efi'eot radial separation thereof for releasing the contacts and breaking the circuit through the same, and means responsive to a predetermined flow oi current through said contacts for retaining said annular member in inoperative position during current flow below a predetermined amperage and for releasing said member upon fiow of current above said predetermined amperage.

13. A circuit breaker comprising a pair of concentric contacts, the inner of said contacts being spring actuatable in an axial direction from circuit closingposition, the outer of said contacts being radially distensible and arranged normally for engaging said inner contact to retain the same in circuit closing position, an annular spring-actuated intermediate member slidable axially between said contacts for effecting radial distension of said outer contact to open the cirr cult and release said inner contact for spring actuation from circuit closing position, a catch member normally retaining said intermediate member in inoperative position against spring actuation, and means responsive to predetermined circuit overload for eil'ecting the release of said intermediate member.

14. A circuit breaker comprising a casing, a

pair of circuit closing contacts therein having portions arranged for interengagement for retaining the same in circuit closing position during predetermined circuit loads, one of said contacts being spring actuatable from normal circuit closing position and provided with a resetting member movable outwardly of the casing, a spring actuated member slidable intermediate said contacts for opening a circuit through the same and effecting the disengagement of said first contact for spring actuation of said resetting ,member outwardly of the casing, catch comprising an indicating member, and a spring actuatable thermostatically controlled annular contact-separating member arranged for telescopic movement along said movable contact to effect separation of said contacts to-break a circuit through the same upon predetermined circuit overload and to disengage said contacts for spring actuation of said movable contact and said indicating member from normal position.

16. A circuit breaker comprising a pair of contacts having coacting portions for releasably retaining the same normally in circuit closing relation, one of said contacts being movable from normal position, a spring tending to move said movable contact from said position, a spring actuatable contact-releasing member for efiecting the release of said contacts for movement of said movable contact -from circuit closing position, catch means for retaining said releasing member normally in inoperative position against the action of the spring thereof, and means responsive to a circuit overload for actuating said catch means for freeing said contact-releasing member.

1'1. A circuit breaker comprising a casing provided with an apertured cover and a pair oi terminals, one of said terminals comprising a threaded shell, a pair of circuit controlling contacts in said casing, one of said contacts having a radially distensible annular portion for normally engaging the other contact .to close the circuit therethrough and to retain the contacts in circuit closing relation, said other contact being movable axially' of said first contact, an

indicating member secured to said second contact .and movable within said aperture, a spring tending to move said member outwardly through said aperture and said second contact from normal circuit closing position, a heating element in said casing electrically connected with said terminals, a thermostatic element adjacent said heating element and movable in response to a predetermined heating efiect of said element, a spring actuatable annular insulating member movable between said contacts to distend said annular portion o'i' said first mentioned contact to open the circuit therethrough and release said second contact, and a catch member controlled by said thermostatic element and arranged to retain said insulating member in inoperative position during normal circuit loads and to release said member upon overload for actuation by the spring thereof.

18. A circuit breaker comprising a pair of circuit closing contacts, one of said contacts being spring actuatable from a position wherein it is adapted to close a circuit through the other con- .tact, catch means for retaining said contacts normally in circuit closing relation, a manually operable resetting member carried by said movable contact ior restoring said contact to normal position, a catch member, a thermostat arranged to move said catch member to and from operative Position, and a spring operable member adapted to be retained in inoperative position by said catch member during normal circuit loads being spring actuatable from a normal position 10 wherein it is adapted to close the circuit through the other contact, a manually operable resetting member carried by said movable contact for restoring the latter to original position, and a thermostatically controlled spring actuatable member arranged to separate the contacts to break the circuit independently of the movability of said resetting member by said movable contact.

EMIL R. CAPPELLE. 

